1. Field of the Invention
The present invention relates, in general, to a dishwasher and method of controlling the same and, more particularly, to a dishwasher and method of controlling the same, which is provided with a heater to heat washing and rinsing water, and which performs washing, rinsing and drying processes while using the heater.
2. Description of the Related Art
A dishwasher is an apparatus that removes contaminants from dishes by spraying a cool water or a hot water on the dishes disposed on racks in a washing chamber. To remove contaminants, pumps and nozzles are basically required to spray a washing water and a rinsing water, and a heater is required to generate the hot water. Herein is described a conventional dishwasher with reference to FIG. 1.
FIG. 1 is a vertical sectional view of a conventional dishwasher 100. As shown in FIG. 1, a washing chamber 104 having an opening in a front thereof is provided in a body 102 of the conventional dishwasher 100, and a door 106 that is selectively opened or closed is connected to the front of the body 102 with hinges. Dish racks 104a, provided to hold dishes, are disposed in upper and lower portions of the washing chamber 104 to slide in both forward and backward directions. Upper and lower spray nozzles 104c that spray the washing water on the dishes are disposed under the dish racks 104a, respectively.
A heater 150 that heats the washing and rinsing water and therefore generates the hot water is disposed under the dish rack 104a seated in the lower portion of the washing chamber 104. If the washing or rinsing water is supplied into the washing chamber 104 and the heater 150 is submerged under the water, the hot water is generated by a heat exchange between the supplied water and the heater 150. The hot water is used to remove food dregs on the dishes, or to soak dried food dregs in the water and remove the dried food dregs in a washing process. The hot water is used to heat the dishes for a rinsing process. If the dishes are heated using the hot water for a last operation of the rinsing process, water is rapidly vaporized by a latent heat of the dishes in a drying process to be later performed.
A water tank 108 is disposed in a separate space under the dish rack 104a seated in the lower portion of the washing chamber 104 to contain washing or rinsing water. The water tank 108 is connected to a discharge pump 110 and a water supply pump 112 through a discharge pipe 110a and a circulation pipe 112a, respectively. The circulation pipe 112a is connected to water supply pipes 104b connected to upper and lower spray nozzles 104c, respectively.
With this construction, the washing or rinsing water sprayed from the upper and lower spray nozzles 104c, which is circulated inside the washing chamber 104, passes through the water tank 108 and the circulation pipe 112a, is supplied to the water supply pipes 104b, and then is resprayed by the upper and lower spray nozzles 104c, and is recirculated inside of the washing chamber 104 by an action of the water supply pump 112. When a washing time elapses or a rinsing time elapses, the washing or rinsing water discharges outside the body 102 of the conventional dishwasher 100 by an action of the discharge pump 110.
In the conventional dishwasher 100 having the heater 150 therein, since the heater 150 is submerged under the water to generate the hot water, compounds of calcium (e.g., calcites) form on a surface of the heater 150, so that a lifetime of the heater 150 is shortened. Further, since the water is directly heated, relatively large periods of time are required to generate the hot water. Further, in a case where air in the washing chamber 104 is heated to perform a drying process using the heater 150, dishes are excessively heated, so that removing the dishes immediately after the drying process is complete is inconvenient for a user.
A model of a convention dishwasher exists in which an exterior heater is installed in a separate space outside the washing chamber and is constructed to supply water heated by the heater to the washing chamber. In this case, since the heater is submerged under the water to generate the hot water, there remains the problems that the lifetime of the heater is shortened by the heater being covered with the calcium compounds, a washing time is increased by a direct heating of the water, and considerable energy is consumed. Further, the conventional dishwasher having the exterior heater rinses dishes using the hot water for the last operation of the rinsing process instead of heating air in the washing chamber to prevent the dishes from being excessively heated for the drying process, so that the dishes are properly heated and will be rapidly dried by the latent heat of the dishes in the drying process to be later performed. As described above, since the conventional dishwasher having the exterior heater dries the dishes using the latent heat, rinsing using the hot water should be performed at the last operation of the rinsing process just prior to the drying process. Accordingly, an independent drying process in which the water is not required cannot be performed. Further, since the rinsing of the dishes using the hot water is performed at the last operation of the rinsing process just prior to the drying process, unnecessary power results, so that an energy consumption efficiency of the conventional dishwasher is decreased.